The present invention pertains to the field of remote condition reporting apparatus. More specifically, the present invention pertains to automatic apparatus for installation at a home or other location remote from utility company and emergency service headquarters, for automatically reporting utility usage information for billing purposes, and for automatically reporting the occurrence of an emergency condition such as fire, burglary, power outage or the like.
Many systems have been composed in recent years for the automatic reading of utility meters, with the intended object of providing more up-to-date information and for eliminating the high labor costs involved in door-to-door meter reading, as well as the occasional inconvenience to customers. However, despite the great number of systems and devices which have been proposed in the prior art, and the many patents granted thereon, none of these systems have come into widespread use. Except for a few small scale experimental usages, automatic meter reporting systems have been limited to large scale industrial users where it has been feasible to install expensive equipment, dedicated leased telephone lines and the like.
However, systems for installation in homes must deal with additional constraints. For one thing, the cost of the equipment to be installed in each home must be low enough so that it is economically feasible and advantageous for a utility company to make the initial investment, as compared with the labor costs involved in door-to-door meter reading. For another thing, the equipment installed at the home must be compatible with normal home telephone usage and normal home telephone line service. Obviously any system which unduly interferes with the normal flow of outgoing and incoming calls to the home would be unacceptable to the consumer and to the telephone company. On the other hand, any system which requires the installation of special or additional lines to each home or the addition of special switching equipment at the telephone office is objectionable from a cost viewpoint. Further, to justify the expense involved with the home reporting units, they should be flexible enough in design to permit reporting of different types of data to different destinations, and they should permit easy adaptation or modification for adding additional services or functions as they may be developed, without having to make obsolete and replace all home units.
Most prior art reporting systems involve polling or interrogating home units from a central office computer. In such systems, special equipment installed at, for example, a power company would sequentially dial-up each customer's phone on a monthly basis, and a reply unit at the home would upon command send out coded data corresponding to the meter reading. One problem with this type of system is the problem of the ringing of the home phone during the machine interrogate process. If the customer's phone is allowed to ring on a meter reading interrogation call, this presents a constant source of nuisance to the customer. Additionally, if the customer answers the phone while data is being transmitted, it may interrupt such transmission and necessitate the repetition of the call, thereby creating further nuisance. It is for this reason that most telephone companies have adopted operating rules which prohibit usages which would create nuisance ringing at the customer's phone.
Systems have been proposed which avoid the ringing of the customer's phone by accessing the test train of the telephone system network. Although this approach would avoid the problem of nuisance ringing at the home, it suffers a number of disadvantages. For one thing, there is the additional expense involved in installing equipment to access a test path. Another problem is that this additional equipment must be at the telephone company's central office, rather than at the office of the utility company involved. This creates another problem, that of coordinating use of the equipment by more than one utility. For these reasons, these types of systems have not been widely adopted.
Other types of prior art devices would attempt to avoid the nuisance ring problem by suppressing the first ring of the telephone. These systems then present the problem of how to distinguish between ordinary telephone calls and those from the utility company, so that the ring can be restored for ordinary calls. The application of a device of this type would require suppression of the first ring of every incoming call, and this practice is generally against the operating rules of most telephone companies.
Other systems have sought to avoid the above problems by initiating the reporting call from the home, rather than from the utility company office. However, the prior art systems thus proposed have certain disadvantages, including the difficulty of precisely controlling the time of day or night or the exact day of the month for initiating the reporting call. These systems also involve unnecessary complexity and they lack the flexibility to provide for reporting a plurality of different functions on different reporting periods.
In addition, the initiation of time of day billing rates for normal and for peak power periods in many parts of the country have further complicated the requirements of home reporting systems, which are now required to report both on-peak period usage and off-peak period usage.